Process of splicing tow



March 14, 1967 D. c. GAGNON 3,308,520

PROCESS OF SPLICING TOW Filed Feb. 10, 1965 2 Sheets-Sheet 1 FIG-1 INVENTOR DAVID C. GAGNON BY Mi ATTORNEY March 14, 1967 c) GAGNQN 3,308,520

PROCESS OF SPLICING TOW Filed Feb. 10, 1965 2 Sheets-Sheet z INVENTOR 32 25' 32 DAVID c. GAGNON BY W QM ATTORNEY United States Patent 3,308,520 PROCESS OF SPLICING TOW David C. Gagnon, Greenville, N.C., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Feb. 10, 1965, Ser. No. 431,545 2 Claims. (Cl. 28-722) This invention relates to the processing of large bundies of filaments, and is more particularly concerned with a process for splicing rope and ends preparatory to cutting the tow filaments into staple.

Synthetic polymers are spun into continuous filaments at high speeds. The filaments are cut into staple fibers for many textile uses, as for blending with cotton or wool. One form of apparatus for cutting continuous filaments into staple is illustrated in Hull US. Patent No. 2,694,447 dated November 16, 1954. The rate of feed through staple cutters is much slower than the production rate of drawing machines, so the operations are performed independently of each other. It is conventional to accumulate filaments from a drawing machine in a container, as by piddling the bundle of filaments into a large box, which is then moved to a staple cutter at a different location. Bundles of ropes of filaments from several containers are combined into a large tow and fed to the cutter. Rope ends must be joined at the beginning of each new pid-dle box and, in addition, joints are required due to interruptions in spinning, sampling or removal of any defects which occur during spinning or drawing.

The bundles can be joined by tying knots. However, the knots cannot be passed through the staple cutter; so the cutter must be shut down to remove knots. Inaccurate cut lengths result while the cutter is slowing to a stop or speeding up when restarted, so this material is also rejected. Material diverted to waste in this way may amount to as much as /2% of the production. Furthermore, such interruptions may reduce the cutter efficiency by as much as 6%. Tow ends could be joined by a sown thread and tape splice, but this type of splice cannot be cut for fear of thread or tape contamination in the product and would have to be removed prior to the cutter in the same manner as knots.

The present invention overcomes the above difiiculties by a new type of splice which can be fed through the staple cutter While operating at full speed without damaging the cutter blade. The splice has adequate strength to withstand cutter feeding tensions and is free from materials which could contaminate the cut staple. Furthermore, the process can be operated so that the cut splices are automatically removed from staple leaving the cutter when desired. Other advantages will become apparent from the specification and drawings.

In the drawings, which illustrate the manner of making the splices and suitable apparatus for accomplishing this,

FIGURE 1 is a front elevation of one form of apparatus for use in the process,

FIGURE 2 is cross-sectional detail taken on line 22 of FIGURE 1,

FIGURES 3 to 6 are diagrammatic illustrations of the process, a single felting needle being shown for clarity, and

FIGURE 7 illustrates a finished splice.

The present invention is an improvement, in the process of cutting continuous filaments into staple, of joining the ends of filament bundles by overlapping two ends to point in opposite directions with a 3- to 12-inch overlap and punching felting needles repeatedly through the overlapping portions to form a splice, and then passing the spliced tow continuously through the staple cutter to 3,308,520 Patented Mar. 14, 1967 cut all of the filaments, including those in the spliced portion. Preferably, especially for tows of 500,000 denier and up, the splice is formed by usingg 50 to felting needles arranged in 5 to 10 rows and punching the needle assembly through the two filament bundles 10 to 100 tunes to interlock the filaments.

The above splice is composed of the same filaments as the tow and they are essentially aligned in the same manner. Hence they can be cut into staple fibers along with the other filaments without interrupting the normal operation of the cutter, without damaging the cutter blades, and without contaminating the product. Staple cutters of the type provided with automatic mechanism for ejecting harsh tow, from the product leaving the cutter, can be adjusted to divert fibers from the spliced portion to waste, but this is necessary only for the most rigorous quality standards.

The splicing apparatus embodies some features of needle felting machines used for continuous processing of webs into nonwoven fabrics of felts of up to 300 inches in width. However, apparatus suitable for use in the process of the present invention is designed to provide fiber-interlocking over a width of less than 6 inches, and for intermittent use on stationary lapped filament bundles. Referring to FIGURE 1, a battery of felting needles, arranged in uniformly spaced rows, is mounted on plate 11. The plate is secured to rod 12 which is attached to piston 13 for reciprocating the needles up and down. The piston is operated by pneumatic pressure within cylinder 14 mounted on frame 15. Means for controlling the pneumatic pressure is indicated schematically by supply piping 16, 17, and 18, vent 19 and valve 20. The material to be spliced is supported between a stripper plate 21 and a bed plate 22, both perforated to pass the needles 10. The bed plate may be supported on crank means, indicated generally by 23, for separating the plates to receive lapped filament bundles and for closing the plates together for clamping the material in place, if so desired.

FIGURE 2 is a side view of plates 21 and 22 in the closed position with tows 24 and 25 in lapped relation between the plates. The needles 10 are shown in the penetrating position near the bottom of their travel. The action of a single needle is illustrated in FIGURES 3 to 6, which show lapped tows in position between plates 21 and 22 as in FIGURE 2. In FIGURE 3 needle 10 is shown in its upper position above opening 26 in stripper plate 21. FIGURE 4 shows the needle after it has descended through the stripper plate and is starting to project through opening 27 of bed plate 22. Needle barbs 28 and 29 have caught on tow filaments and are pulling them downward with the needle. In FIGURE 5 the needle has punched through the tows to the lowest position of travel, pulling a group of filaments 30 downward with it. FIGURE 6 the needle is moving upward leaving a group of filaments 31 projecting through opening 27 of bed plate 22. Repeated needle punches would be required to provide the extent of filament rearrangement illustrated in FIGURE 6.

The appearance of the completed splice is illustrated in FIGURE 7. The tows 24 and 25 are secured together by the needle-punched portions 32, where the filaments are firmly interlocked.

Example Ends of 700,000 denier, multifilament polyethylene terephthalate tow are spliced by needle punching as indicated in the table. The position of the tows is not changed during the splicing operation. Needle rows are spaced /2-inch apart. The needles used have a 15 gauge shank, an 18 gauge intermediate blade and 30 gauge blade, 3% inches long, with close barb spacing; have swaged barbs of medium throat; depth and have a plain steel finish. Typical splice strengths resulting from the various treatments are shown. A strength of 30 pounds is sufficient for most purposes.

TABLE Needle Needle Splice Rows Punches Strength (Number) (Number) (Pounds) Tows as small as 100,000 total denier or as large as 1,000,000 total denier or even larger may be spliced satisfactorily by the process of this invention.

Since many different embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

I claim:

1. In the process of preparing staple fiber by assembling multifilament ropes of synthetic filaments into a tow and feeding the tow through a staple cutter, wherein individual lengths of filament bundles are joined end-toend to form a continuous tow for feeding the staple cutter, the improvement of joining the ends of filament 5 bundles by overlapping two ends to point in opposite directions with a 3-inch or greater overlap and punching felting needles repeatedly through the overlapped portions a sufiicient number of times to interlock the filaments to form a splice of at least 30 pounds strength, and passing the spliced tow continuously through the staple cutter to cut all of the filaments, including those in the spliced portion.

2, A process as defined in claim 1 wherein said tow is of at least 100,000 denier.

References Cited by the Examiner UNITED STATES PATENTS 2,608,725 9/1952 Strew 19157 3,017,684 1/1962 Pittman 28-72 3,166,823 1/1965 Bernard 28-72.2

FOREIGN PATENTS 956,992 4/1964 Great Britain.

25 MERVIN STEIN, Primary Examiner.

L. K. RIMRODT, Assistant Examiner. 

1. IN THE PROCESS OF PREPARING STAPLE FIBER BY ASSEMBLING MULTIFILAMENT ROPES OF SYNTHETIC FILAMENTS INTO A TOW AND FEEDING THE TOW THROUGH A STAPLE CUTTER, WHEREIN INDIVIDUAL LENGTHS OF FILAMENT BUNDLES ARE JOINED END-TOEND TO FORM A CONTINUOUS TOW FOR FEEDING THE STAPLE CUTTER, THE IMPROVEMENT OF JOINING THE ENDS OF FILAMENT BUNDLES BY OVERLAPPING TWO ENDS TO POINT IN OPPOSITE DIRECTIONS WITH A 3-INCH OR GREATER OVERLAP AND PUNCHING FELTING NEEDLES REPEATEDLY THROUGH THE OVERLAPPED PORTIONS A SUFFICIENT NUMBER OF TIMES TO INTERLOCK THE FILAMENTS TO FORM A SPLICE OF AT LEAST 30 POUNDS STRENGTH, AND PASSING THE SPLICED TOW CONTINUOUSLY THROUGH THE STAPLE CUTTER TO CUT ALL OF THE FILAMENTS, INCLUDING THOSE IN THE SPLICED PORTION. 